Process of depositing metals upon and in combination with metals or metal articles.



UNITED STATES PATENT FF E.

FREDERI K WILLIAM GAUNTLETT, OF LONDON, ENGLAND, AssIc-NOP.

OF ONE-HALF TO THE SHERARDIZING SYNDICATE LIMITED, or LONDON, ENGLAND.

PROCESS on DEPOSITING Mar ins UPON AND 119 ooMBINArIoN WITH METALS R METAL ARTICLES.

Specification of Letters Patent.

Patented Jan. 19, 1909.

Applipation filed April 16, 1907. Serial No. 368,592.

, fieation.

This invention relates to improvements concerning the deposition of metals in a metallic state upon, and their combination with, metals or metallic articles by the aid of applied heat, and has for its, objectto supersede the known methods whereby for example metal such as iron in a made up form or otherwise and metal in a fine state of division such for instance as Zinc dust are placed in a suitable rece tacle and subjected to the application of heat, for the purpose of depositing the zinc on the iron or other metal.

According to such known methods, the addition to the finely divided metal such as zinc dust or a mixture of zinc and zinc oxid, or cuprous oxid or a mixture of copper and cuprous oxid, or antimony with or Without some oxid of antimony before it is packed with the articles to be treated in-a revolving drum, for example, of a small percentage of carbon has been proposed with the object of combining with any oxygen present in the receptacle during heating, the proportion of the carbon added being 1 to 3 or 1 to 6 per cent. of the amount of finely divided metal employed (see United States Patents Nos.

701,298, and 829,386, and British Patent Specifications No. 9927 of 1901, No. 28,590 of 1903 and No. 13,579 of 1904).

The processes thus referred to, when used for applying a deposit of zinc or analogous metal to the surface of iron or other similar metal tobe coated, are known in the art as dry galvanizing processes. I have found by experiment that these processes are capable of improvement whereby the o eration is put under better control 1 and t e cost thereof is lessened. I have found that it is possible to form an alloy between the coating metal and the metallic surface of the object to be coated without necessarily maintaining all portions of the metallic surface to be coa ed in actual contact with the coating material.

In practicing this invention the finely divided metal to be deposited (hereinafter for convenience called the coating metal) is mixed with a substantial amount equal to and preferablyexceeding that of the coating metal of a substance (not being .an oxid of the coating metal) which is chemically inert with respect to the coating metal at the tern erature necessar for the de osition or P P decremental co1nb1nat1on of the coatln I metal with the metal or metallic article to be coated.

' As examples of substances which answer the requirements of being chemically inert under the conditions specified, carbon and silica in various degrees of fineness may be cited, and thesejsubsta'nces it may be ob: served remain chemically men with respect to the finelydividd coating metal, zine dust say below a temperamreof 1500 F., while I find from experiments that the finely divided coating metal, e. g. zinc dust will combine with the metal or metallic articles at a temperature considerably below that mentioned I above.

It may here be observed that the presence of some oxid of the metal is not adverse to the process; the temperature being such that the carbon material employed will not eifect the reduction of the oxids of the metals. 7

The proportions of the inert substance and the metal in a fine state of division I have found may vary very considerably according to the articular result required to be obtained, but by way of example only, a somewhat general proportion may be taken as be- 111g rune the chemically inert substance to. one part or thereabouts of the finely divided metal or.

metals. I

In effecting the combination of the finely divided coating metal with the metal in made up form or otherwise the latter is inclosed with the mixture in a suitable receptacle and subjected to heat, as by placing the receptacle in a gas or otherwise -eated oven.

Taking as a typical example, the coating of iron or steel with zinc by employing in the manner indicated a mixture of nine parts by volume of sand and one art by volume of zinc dust, the receptacle m' which the metal or metallic articles and the mixture are placed is heated up to a temperature of about 700 F. for about one hour. The duration arts by volume or thereabouts of the results metalwith, and its deposit on and temperature of heating is however even in this example .very considerably variable according, for instance, to the dimensions of the receptacle and the depth 'of coating required.-

By theprocess according to this invention secured generally, and those particularly pertaining to the cost of effecting the combination of the finely divided coating metal or metallic articles and the qualities and properties of the articles'treated accordingrto the process constitute an important advance in the art. The results obtained may be also greatly varied according to ta) the fineness or coarseness of the inert substance, (b) the time of treatment, (a) the heat to which the articles and mixture are subjected and (cl) the variation in the proportion of the inert substance tothe coating metal. In this lat ter connection I may observe that, other things being equal, as the pro ortion of the coatingmetal to the inert su stance is reduced the greater it is believed is the alloy between the divided coating metal and the metal or metallic articles.

It is impossible to state the exact conditions necessary to meet each particular case as the exact conditions vary With the metals employed and the proportions of the inert material and the results required but in each case the Working conditions for effecting the object desired can be ascertained by one or two trial experiments.

What I claim and desire to secure by Letters Patent is 1. The rocess of' depositing metals upon metals, w ich process consists in applying to the metal to be coated a mixture of thecoating metal or metallic compound in finely divided form, and a large uantity of a substance, not being an oxi of the coating metal, which is chemically inert to the coating material at the temperatures necessary for depositing the metallic coating upon, and in combination with the foundation metal, and submitting the whole toheat, the inert substance being present in a quantity equal to and preferably in excess of coating material, substantially, as described.

2. The process of depositing zinc upon iron, steel or other metal, which process consists in applying to the metal to be coated zinc dust or finely divided zinc mixed with a substance, not bei" g an oxid of the coating metal, which is'inert to the zinc dust or finely divided zinc at the temperature necessary for depositing the metallic coating upon and that of the i in decremental combination with the foundation metal, and. submitting the whole to heat, the inert substance being, resent in a quantity at least equal to that of metal, substantially as described.

3. The process of depositing metals upon metals, which process consists in applying to the metal to be coated a mixture of the finely divided coating metal or metallic compound and sand or other form of silica or like material in quantity at least equal to said coating metal or compound, and submitting the Whole to heat, substantially -as described.

In witness whereof I have hereunto signed my name in the presence of two subscribing Witnesses.

;FREDERICK WILLIAM GAUNTLETT. Witnesses: 1

ROBERT MILTON SPEARPOINT H. D. JAMESON. I

the coating 

